Preamp vs. Fader

[jaba]

This may sound stupid,.....BUT:

I need to raise the dial REALLY high on my presonus firepod preamp to get enough sound on my ribbon microphone and I notice that at the last several notches, the amount of "hiss" increases a lot. But I need that much gain.

I'm wondering what is wrong with the idea of recording with a low level of gain and raising the faders a lot.

Thanks.

 

[distortedrumble]

ribbon mics take phantom power dont they? does the firepod have phantom power?

 

[sile2001]

ribbon mics take phantom power dont they? does the firepod have phantom power?

I don't think he would be getting any signal at all if phantom power wasn't turned on.

 

[mshilarious]

This may sound stupid,.....BUT:

I need to raise the dial REALLY high on my presonus firepod preamp to get enough sound on my ribbon microphone and I notice that at the last several notches, the amount of "hiss" increases a lot. But I need that much gain.

Yes.

I'm wondering what is wrong with the idea of recording with a low level of gain and raising the faders a lot.

Well, that's just another gain stage, which may or may not be noisy itself, or you might be amplifying noise from the previous gain stage. But if it works, there you go.

 

[Sklathill]

Ribbon mics do NOT need phantom power. As a matter of fact, many older ribbons (and possibly some new ones, I don't know) will just go bye-bye if exposed to phantom power.

Also, ribbon mics need LOTS of gain...just a fact of nature. it's also a fact that most lower cost preamps including those included on sound cards just don't sound all that good on the extreme high end of their gain pot. I would suggest trying another preamp. I know Harvey Gerst uses a VTB-1 solely to preamp his AEA ribbon...

 

[cominginsecond]

ribbon mics take phantom power dont they? does the firepod have phantom power?

Only a couple take phantom. In fact, there have been cases where phantom power blows up ribbons.

 

[Halion]

I don't think he would be getting any signal at all if phantom power wasn't turned on.

Dudes, check your fact! He could have destroyed his mic! If you don't know your stuff, don't advice.

 

[Track Rat]

Dudes, check your fact! He could have destroyed his mic! If you don't know your stuff, don't advice.

Precisely.

 

[jpfour23]

Not sure about the firepod, but you might just need a preamp. I use to have all kinds of gain problems back when I had a vs2480... The preamps were lousy.. I too had to get the trim around 4-5 o'clock for certain sessions. It annoyed me.

Then I got a preamp and have all the headroom i need. Some of this also depends on the mic you're using.

 

[noisedude]

This is interesting. I was considering a Firepod for my next interface but if the preamps don't have the necessary gain ...

 

[xstatic]

Not to defend the Presonus, but the original poster is talking about need ing a lot of gain for a RIBBON mic. This is a normal thing. Now, if he were using a low ouput ribbon mic at a distance on a fairly soft source, ANY preamp would be pressed to get enough signal without being laid in to. Lets just get the facts straight before we start making assessments

 

[mshilarious]

Then I got a preamp and have all the headroom i need. Some of this also depends on the mic you're using.

A couple of things:

- Gain and headroom aren't the same thing. Headroom is max level before clipping, and has more to do with handling of loud transients than gain. It's not all that relevant in the digital domain, since you've gotta watch 0dBFS. For example, the Firepod is 0dBFS = +18dBu, but the analog specs list +22dBu headroom. So your analog signal isn't clipping at +20dBu, but the digital signal is. So what's the value? Well, if you're running a compressor off the insert, then you don't want the preamp to clip the loud transient, you want a clean signal that the compressor can stuff back into the +18dBu digital max.

In any event, if you don't have enough gain, then you have plenty of headroom!

- Presonus has units that have enough gain for ribbons, but the Firepod isn't one of them. Its specs list max gain of +54dB, whereas ribbons are gonna be happier with a unit like the MP20 which is +72dB.

 

[sweetnubs]

gawd, precisely my complaint with audio websites: the spread of mis-information. Gawd don't post information if you do know what you are talking about. Gawd, like ribbons are dynamic mics and do not require power like their capictor cousins. Except, like gawd, I think Royer started making a phantom powered one, but I am not sure. (like saying things like "I'm not sure" I qualify my statement with the indication that this is not emperical truth but I believe it to be true therefore it may not be) Gawd, send phantom power to older ribbon mics and watch a mushroom cloud form. Ok I am exaggerating for effect but you will kill it. Ribbon mics generally require lots of gain especially on quiet sources, your standard 60db gain preamp may not be enough. The headroom/gain misonomer was covered quite well so I won't go into further. Ok! Gawd. Also fiddling with with various gain/fader levels is a big no no. Like gawd there is only one way to set levels. I repeat one way. The fader must be set at unity gain which is generally indicated on your console (a 0, fatter or longer line, U for you mackiods, etc.) The fader always stays here when recording (except for special exceptions or in exceptional cases which is the one exception to the rule). Once your fader is set then you turn up the trim on your preamp until you get the desired level. That's it kiddies. Isn't science fun! The hiss you are getting is most likey due to crappy gain structure. See my level setting turtorial above. Or your preamp is a noisy peice of crap. Or your mic is a noisy peice of crap. ok! Gawd!

 

[noisedude]

Sweetnubs, I mean Ed, I mean Father Time, I mean DJ Fingaz, I think I want to marry you.

 

[mshilarious]

Sweetnubs, I mean Ed, I mean Father Time, I mean DJ Fingaz, I think I want to marry you.

Meh, I dunno. Does he have the hotness?

 

[dgatwood]

- Presonus has units that have enough gain for ribbons, but the Firepod isn't one of them. Its specs list max gain of +54dB, whereas ribbons are gonna be happier with a unit like the MP20 which is +72dB.

While it is usually true that a larger max gain means that the manufacturer took a little more care in design, it isn't necessarily so. The critical figure here is the ratio of the input level to the noise floor. That ratio is the signal-to-noise ratio. If your noise floor isn't a -lot- lower than your input level, you can have all the gain in the world and it will still sound like crap. I -think- (though I haven't tried) that I could drive an LM741 op amp up to 72dB of gain. That doesn't mean you'd like the output.

WRT blowing ribbons with phantom power, it shouldn't unless the mic is miswired. The voltage should cancel itself out in the transformer if everything is wired correctly; there shouldn't be any direct DC path across the ribbon to ground from either of the two signal lines. I'm not saying using phantom power on ribbons is a good idea, particularly if you aren't certain that your mics and cables are wired correctly, but... I wouldn't expect any damage if your mic actually came with an XLR connector from the factory. (Hand-rewired vintage mics are a different story, depending on who did the rewiring. )

 

[xstatic]

Whereas leaving the fader at 0 during tracking is fairly standard practice, by no means is it necessary. Alot of that decesion is made by the quality of the preamp, the headroom, and by the tone desired.

 

[acorec]

This may sound stupid,.....BUT:

I need to raise the dial REALLY high on my presonus firepod preamp to get enough sound on my ribbon microphone and I notice that at the last several notches, the amount of "hiss" increases a lot. But I need that much gain.

I'm wondering what is wrong with the idea of recording with a low level of gain and raising the faders a lot.

Thanks.

Ribbon mics don't have self-noise but they do require a very healthy pre-amp. This is one place where a good high end pre-amp is very necessary. The pre-amp must have very high gain and very clean gain.

 

[mshilarious]

While it is usually true that a larger max gain means that the manufacturer took a little more care in design, it isn't necessarily so. The critical figure here is the ratio of the input level to the noise floor. That ratio is the signal-to-noise ratio. If your noise floor isn't a -lot- lower than your input level, you can have all the gain in the world and it will still sound like crap. I -think- (though I haven't tried) that I could drive an LM741 op amp up to 72dB of gain. That doesn't mean you'd like the output.

That's a good point. I have experience with the MP20 - ribbon mic combo, and it works well. It would be a decent choice for a couple of extra preamp channels for the ribbon mic.

I also used to have the Digimax LT, those preamps are very "meh" compared with the MP20. I bet the Firepod probably uses the same pre as the LT.

 

[sweetnubs]

x-static I call bullshit on you. The fader is left here because it is the unity gain position. The manufactuer is telling you the console runs most effeciently at this point to keep the explanation simple. To move the fader off unity gain is to introduce more noise. That's it. Plain and simple. It's not about what you feel like doing, it's pure and simple science mr. bullshit man. Of course if you are not getting enough gain from your preamp you can boost the fader if you wish but this is an exception. I suppose if you want to introduce hiss for creative purposes (whatever, gawd!) that's ok. During mixing the faders can be moved into all kinds of hott positions. When you see someone properly tracking all the faders will be lined up in a neat little row. Gawd! acorec: All mics have self-noise. Some more than others. All electronic devices have self-noise. It is inherent. Gawd!